1. Field of the Invention
The present invention generally relates to instruments and methods used during a spinal stabilization procedure to manipulate vertebrae. More particularly, the present invention generally relates to spinal surgical procedures that use instruments and methods for adjusting a separation distance between adjacent vertebrae.
2. Description of Related Art
Bone may be subject to degeneration caused by trauma, disease, and/or aging. Degeneration may destabilize bone and affect surrounding structures. For example, destabilization of a spine may result in alteration of a desired spacing between adjacent vertebrae. Alteration of a desired spacing between adjacent vertebrae may subject nerves that pass between vertebral bodies to pressure. Pressure applied to the nerves may cause pain and/or nerve damage. Maintaining the desired spacing between vertebrae may reduce pressure applied to nerves that pass between vertebral bodies. A spinal stabilization procedure may be used to establish and/or maintain the desired spacing between vertebrae and promote spinal stability.
Spinal stabilization may involve accessing a portion of the spine through soft tissue. Conventional stabilization systems may require a large incision and/or multiple incisions in the soft tissue to provide access to a portion of the spine to be stabilized. Conventional procedures may result in trauma to the soft tissue, for example, due to muscle stripping.
U.S. Pat. No. 6,530,929 to Justis et al. (hereinafter “Justis”), which is incorporated by reference as if fully disclosed herein, describes minimally invasive techniques and instruments for stabilizing a bony structure in an animal subject. Justis provides a method for using an instrument to connect at least two bone anchors with a connecting element. The instrument is secured to the anchors and manipulated to place the connecting element in a position more proximate the anchors. The Justis system is a constrained system. An elongated member installed using the Justis instruments and method must have a set curvature to function with the installation instruments.
U.S. Patent Publication No. U.S. 2004 0138662 to Landry et al. (hereinafter “Landry”), which is incorporated by reference as if fully disclosed herein, describes a minimally invasive procedure and instruments for stabilizing a portion of the spine. The Landry system is not a constrained system. An elongated member installed using the Landry instruments and method does not need to have a curvature defined by the insertion instruments.